The lung is the essential respiratory organ. The principal function is to transport oxygen from the atmosphere into the bloodstream and to release carbon dioxide from the bloodstream into the atmosphere. In order for gas exchange to occur, the lung maintains a highly specialized barrier between the atmosphere and fluid-filled tissues. The terminal airspaces of the lung (alveoli), where gas exchange occurs, provide this barrier. The alveoli are covered by a layer of epithelial cells, alveoli epithelial cells (AECs). AECs act as barrier to fluid leakage and regulate ion transport to promote absorption from the alveolar space to enable proper gas exchange. Conversely, insults that compromise the alveolar epithelial barrier promote accumulation of fluid within the air space that severely compromises respiration.
Acute respiratory distress syndrome (ARDS) is characterized by a severe deficiency of oxygen in the bloodstream caused by alveolar inflammation resulting in the accumulation of fluid in the airspaces. ARDS is associated with mortality. Thus, there is a need to identify therapeutic strategies.
Wang et al. report heterogeneity of claudin expression by alveolar epithelial cells. Am. J. Respir. Cell. Mol. Biol. 29, 62-70 (2003).
Fernandez et al. report chronic alcohol ingestion alters claudin expression in the alveolar epithelium of rats. Alcohol 41, 371-379 (2007).
Baumgartner et al. report D-peptide analog of the second extracellular loop of claudin-3 and -4 leads to mislocalized claudin and cellular apoptosis in mammary epithelial cells. Chem. Biol. Drug Des. 77, 124-136 (2011).
References cited herein are not an admission of prior art.